Obturator

ABSTRACT

An obturator for closing an opening, especially of use in an electrical plug socket adaptor, the obturator comprising in combination three apertured plates in which the apertures are able to be aligned so that entry from the apertures of the first plate to the apertures of the third plate via the apertures of the second plate is only possible by movement of the second plate; in the natural condition of the obturator entrance to the apertures of the third plate is obstructed by the second plate.

This invention relates to an obturator, that is to say an artificial device for stopping an opening. It is more specifically related to the need required at law for the closing of openings in various electrical devices that would lead directly to one or more live members of an electrical supply and hence form a hazard, especially to children. It may be used to advantage at the end of an electrical plug suitable for use with a variety of electrical outlets and configurations for electrical supplies around the world.

According to the present invention there is provided an obturator comprising in combination an apertured first plate that has an aperture aligned or able to be aligned with an aperture third plate between which is juxtaposed a second plate that obstructs entry from said aperture of said first plate to the aperture of said third plate, said first plate being movable to allow said aperture therein to be aligned with an aperture in said second plate thereby permitting entry therethrough so that when said first and second plate are moved together entry may be made from their apertures to the aperture of said third plate.

In an improved obturator for use especially in certain stringent electrical conditions wherein each of the apertured plates have two apertures to receive two prongs of an electrical connector the apertures of the second plate are not rotatable or slideable to uncover the apertures in the third plate until detent means operable by the two said prongs are actuated. The detent means may conveniently be spring actuated members moveable in the direction of entry of the said prongs.

The invention will be more fully understood from the following description given below by way of example only with reference to the figures of the accompanying drawings in which:

FIG. 1 is an exploded view in oblique perspective of an obturator of the invention;

FIG. 2 (comprising FIGS. 2A₁ to 2D₃) is a schematic showing a sequence of operations when the obturator is in use with a plug;

FIG. 3 is a view in oblique perspective of an obturator of FIG. 1 fitted to a simple plug, and

FIG. 4 is a view in oblique perspective of an obturator of FIG. 1 fitted to a complex adjustable plug for use with the various electrical outlets sockets of various countries of the world.

FIG. 5 is an exploded view of an improved obturator similar to that shown in FIG. 1 with axial detent means.

FIGS. 6A, 6B, 6C, 6D are four views of an alternative detent means to that shown in FIG. 5.

Referring now to FIG. 1 an obturator is seen to comprise five members, a shutter ring A, a first plate B, a spring C, a second plate D and a third plate E. Shutter ring A contains a key K, that is aligned with a keyway recess K₁ in the first plate B and K₂ in the second plate arc. A further keyway recess K₃ in third plate E (shown dotted) aligns exactly with key K. Two diametrically disposed apertures b₁, b₂, d₁, d₂, e₁, e₂ are formed respectively in each of the three plates B, D and E and these are identical in size and form, but their disposition in respect of the keyways K₁, K₂, K₃ are different. First plate B has a central spigot S which mates with central holes H₂, H₃ in plates D and E respectively. Spigot S also receives helical spring C the tines T₁, T₂ of which are placed respectively in slots SL₁, SL₂ so that when assembled, plates B and C are spring urged and disposed as explained below with special reference to FIGS. 1 and 2.

Consider a two pronged plug P₁, P₂ (FIG. 2A₁) being entered at apertures b₁, b₂ of first plate B said prongs P₁ P₂ can not pass because they are blocked by the second plate D (FIG. 2A₂) and hence the said prongs P₁, P₂ cannot connect with electrical contacts at apertures e₁, e₂ of third plate E (FIG. 2A₃).

Consider now that the prongs P₁, P₂ are made to rotate first plate B through about a right angle to the position B₁ (FIG. 2B₁) by virtue of keyway recess K₁. The rotational position of the plate is made clear by the circular identification dot on its periphery (marked I₁ in FIG. 2A₁ only) so that apertures b₁, b₂ are now aligned with apertures d₁ d₂ in second plate D (FIG. 2B₂) the position of this plate in rotation may be followed from the square identification dot on its periphery (marked I₂ in FIG. 2A₂ only). The prongs P₁, P₂ cannot, however, enter the electrical contacts at apertures e₁ e₂ (FIG. 2B₃) since they are blocked by the third plate E.

Consider further that both plates B and D are now rotated together (FIGS. 2C₁, 2C₂) through about a right angle by the prongs P₁, P₂ and that apertures b₁ b₂ and d₁ d₂ are now aligned with apertures e₁ e₂ so that the prongs P₁, P₂ now are able to be forced into contacts at e₁ e₂ of plate E (FIGS. 2C₁, 2C₂, 2C₃). Let the prongs P₁, P₂ now be withdrawn (FIGS. 2D₁, 2D₂, 2D₃). Clearly first plate B (FIG. 2D₁) is as it was ab initio in FIG. 2A₁ ; but second plate D now rotates from position 2C₂ to 2D₂ under the action of spring C to the position that it enjoyed in FIG. 1. The position as shown in FIGS. 2D₁, 2D₂, 2D₃ makes it abundantly clear that entry to electrical contacts at e₁, e₂ (FIG. 2D₃) is not now possible since entry apertures b₁ b₂ (FIG. 2D₁) are obstructed by second plate D the apertures d₁ d₂ (FIG. 2D₂) being out of alignment with both b₁ b₂ and e₁ e₂.

In FIG. 3 a simple two prong adaptor plug shown generally at 100 is fitted at 101 with an obturator as shown in FIGS. 1 and 2. When prongs P_(A) P_(B) are entered into an electrical outlet the obturator 101 via first plate B and entry apertures b₁ b₂ prevent an appliance being connected to the supply unless the sequence of events described above with regard to FIGS. 2A₁ to 2D₃ inclusive are effected.

In FIG. 4 a complex adaptor plug shown generally at 200 is used to meet the needs of various electrical outlet configurations around the world, said plug contains right cylindrical prongs (not shown ) of two sizes and spacings together with rectangular prismatic prongs P_(C) P_(D) able to take up a variety of angular dispositions shown in FIGS. 1 and 2. When prongs P_(C), P_(D) are entered into an electrical outlet the obturator 201 via first plate B and entry apertures b₁, b₂ prevent an appliance being connected to the supply unless the sequence of events described above with regard to FIGS. 2A₁ to 2D₃ inclusive are effected.

Clearly the angle shown between the position of plate B in FIGS. 2A₁ and that of FIGS. 2B₁ may be exactly a right angle provided the recess K₁ is greater than a right angle by the width of key K in ring A.

It is to be understood that the obturator of FIG. 1 may have utility in a wide variety of applications, for example it may make a safety lid to a bottle or box containing medicaments in pill, lozenge or capsule form; the stopping of the opening preventing access by a child, but giving ready access to an adult using a prong like opening means and with a knowledge of for example the sequence of events expressed in FIGS. 2A₁ to 2D₃.

It can be shown that a two pronged electrical plug (FIG. 3) for example may be positively yet foolishly used such that one prong only (P_(A)) when inserted at aperture b₁ for example (FIG. 1) may be used to rotate the first plate and place the prong (P_(A)) into an electrically live condition with the other prong (P_(B)) also live yet outside the adaptor case and thus exposed to the operator.

To prevent such a situation arising an obturator as shown in FIG. 5 may be used. Third plate E₁ is provided with detent means comprising a pair of protuberances P₁, P₂ each having a base part P₃, P₄ that is in effect a spring plate to helical compression springs P₅, P₆ that apply force axially of the obturator along axis A₁, A₂ and about the end of the obturator case not shown.

It is clear that rotation of the second plate cannot take place until protuberances P₁, P₂ are each removed from apertures d₁, d₂ of the second plate; to do this both prongs of an entering plug must simultaneously depress P₁, P₂ from out of the apertures d₁, d₂ before it can be rotated. If a single prong were to be inserted then the removal of a single protuberance would leave the other protuberance within an aperture and rotation of the second plate would not be possible.

In FIGS. 6A, 6B a third plate E₁ has detent means comprising a pair of leaf spring members E₂, E₃ forming protuberances the hinge line h₁, h₂ being staggered asymmetrical of the centre line of the plate. In FIG. 6C the hinge line h₃, h₄ is asymmetrical of the centre line of the plate. These plates may be of integral construction and made from nylon for example. 

I claim:
 1. An obturator, comprising:an outer housing having an inner surface with a key means extending inwardly of said inner surface; an outer first plate rotatably disposed in said housing, having a first arcuate keyway for cooperating with said key means to allow limited rotation of said first plate with respect to said housing, two apertures for accepting prongs, and first means for anchoring a spring; a second plate rotatably disposed in said housing adjacent said first plate, having a second arcuate keyway for cooperating with said key means to allow limited rotation of said second plate with respect to said housing, two apertures for accepting prongs capable of alignment with the apertures of said first plate, and second means for anchoring a spring; spring means cooperating with said first and second means for anchoring for rotatably urging said first and second plates to a first position in which the apertures of said first and second plates are not aligned; an inner third plate fixed with respect to said housing adjacent said second plate, having a first pair of apertures for accepting prongs capable of alignment with the apertures of said second plate but being unaligned with the apertures of said second plate when said second plate is in said first position; and two reciprocating detents extending from the surface of said third plate, each having a first end which extends into one of the apertures of said second plate when said second plate is in said first position, to prevent rotation of said second plate, whereby said first plate may be rotated against the bias of said spring means by prongs situated in the apertures of said first plate so that the apertures of said first plate become aligned with the apertures of said second plate, whereupon the ends of said reciprocal detents may be moved toward said third plate by the prongs and said first and second plates may be rotated with respect to said third plate by the prongs so that the apertures of said second plate are aligned with said first pair of apertures of said third plate, relative rotation between said second and third plates being prevented unless each of said detents is moved.
 2. An obturator as claimed in claim 1, wherein said third plate is provided with a second pair of apertures aligned with the apertures of said second plate when said second plate is in said first position, with said detents extending through said second pair of apertures and being resiliently urged by springs.
 3. An obturator as claimed in claim 2, wherein said first plate is provided with a spigot which extends from the surface of said first plate and said second and third plates are each provided with a central aperture for accepting said spigot, and said spring means is a spring coiled around said spigot. 